Posted by vett on Tuesday, May 31, 2011 at 9:59pm.
in abc, c=60 degrees,a=12, and b=5. find c.

math  MathMate, Tuesday, May 31, 2011 at 10:15pm
We usually use Uppercase letters to represent angles, and lowercase for side lengths.
I resume the question as follows:
in abc, =60°,a=12, and b=5. find c.
We can solve this using the cosine rule:
c²=a²+b²2abcos(C)
Substitute the numbers and take the squareroot of c² to get c.

math  Anonymous, Tuesday, May 31, 2011 at 10:20pm
Use law of cosines:
c^2 = a^2 + b^2  2*a*b*cos(C)
c^2 = 12^2 + 5^2  2 * 12 * 5 * cos(60°)
c^2 = 144 + 25  120*cos(60°)
c^2 = 169  120 * 0.5
c^2 = 169  60 = 109
c = sqrt(109) = 10.4403
Answer This Question
Related Questions
 math  Point X is on side AC of triangle ABC such that <AXB =<ABX, and <...
 math  Point X is on side of line AC of triangle ABC such that <AXB = <ABX...
 Math  1. Find the value of Sin^1(1/2) a. 30 degrees b. 30 degrees c. 150 ...
 Genius Math  Triangle ABC has AC=BC, angle ACB=96 degrees. D is a point in ABC ...
 Math please help  In triangle ABC, we have <BAC = 60 degrees and <ABC = ...
 Geometry  Please answer at least one . PLEASE 1. Triangle XYZ has a right angle...
 math  In triangle ABC, AB=2 square root 2, BC=8,angle ABC=45 degrees.Find area ...
 math please help  Find the area of triangle ABC if AB = BC = 12 and <ABC = ...
 geometry  Find m<ABC if line BD is an angle bisector of angle ABC and m<...
 maths  ABC is an acute triangle with ∠BCA=35∘. Denote the ...
More Related Questions